The Effect of Dynamic Surface Tension and High Shear Viscosity on Droplet Size Distributions Produced by a Flat Fan Nozzle

Viscosity and surface tension are known to have a significant impact on liquid breakup into droplets. However, the droplet size data reported by many authors is more irregular than the data on physical properties. In this study, recent improvements to existing techniques were used to obtain the dynamic surface tension at young surface ages and viscosity at high shear rates, which more closely represents those conditions typically encountered at nozzle orifices. The surface tension and viscosity were measured for a selection of surfactants mixed with water, using an oscillating jet technique and a high shear viscometer, respectively. Droplet size and velocity data for the same mixtures, at known distances from the nozzle, were measured using an Aerometrics PDPA-100 1D. A simple correlation between the physical properties and droplet size distribution parameters was made and showed that droplet size (Dv0.5) increased with increasing surface tension. The range of viscosities tested was too small to obtain any meaningful correlation with droplet size. This study is not intended to provide data for rigorous statistical analysis and interpretation, but is a preliminary step in such an investigation.

Downer, RA Research Associate, Research Assistant, Post-doctoral Research Associate, Head and Professor, Laboratory for Pest Control Application Technology, The Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, OH

Cooper, JA Research Associate, Research Assistant, Post-doctoral Research Associate, Head and Professor, Laboratory for Pest Control Application Technology, The Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, OH

Chapple, AC Research Associate, Research Assistant, Post-doctoral Research Associate, Head and Professor, Laboratory for Pest Control Application Technology, The Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, OH

Hall, FR Research Associate, Research Assistant, Post-doctoral Research Associate, Head and Professor, Laboratory for Pest Control Application Technology, The Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, OH